Merge pull request #2567 from andyliao5555/master

添加0018.四数之和的C语言版本
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程序员Carl
2024-06-26 10:01:20 +08:00
committed by GitHub

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@ -151,6 +151,96 @@ if (nums[k] + nums[i] > target && nums[i] >= 0) {
## 其他语言版本
### C:
```C
/* qsort */
static int cmp(const void* arg1, const void* arg2) {
int a = *(int *)arg1;
int b = *(int *)arg2;
return (a > b);
}
int** fourSum(int* nums, int numsSize, int target, int* returnSize, int** returnColumnSizes) {
/* 对nums数组进行排序 */
qsort(nums, numsSize, sizeof(int), cmp);
int **res = (int **)malloc(sizeof(int *) * 40000);
int index = 0;
/* k */
for (int k = 0; k < numsSize - 3; k++) { /* 第一级 */
/* k剪枝 */
if ((nums[k] > target) && (nums[k] >= 0)) {
break;
}
/* k去重 */
if ((k > 0) && (nums[k] == nums[k - 1])) {
continue;
}
/* i */
for (int i = k + 1; i < numsSize - 2; i++) { /* 第二级 */
/* i剪枝 */
if ((nums[k] + nums[i] > target) && (nums[i] >= 0)) {
break;
}
/* i去重 */
if ((i > (k + 1)) && (nums[i] == nums[i - 1])) {
continue;
}
/* left and right */
int left = i + 1;
int right = numsSize - 1;
while (left < right) {
/* 防止大数溢出 */
long long val = (long long)nums[k] + nums[i] + nums[left] + nums[right];
if (val > target) {
right--;
} else if (val < target) {
left++;
} else {
int *res_tmp = (int *)malloc(sizeof(int) * 4);
res_tmp[0] = nums[k];
res_tmp[1] = nums[i];
res_tmp[2] = nums[left];
res_tmp[3] = nums[right];
res[index++] = res_tmp;
/* right去重 */
while ((right > left) && (nums[right] == nums[right - 1])) {
right--;
}
/* left去重 */
while ((left < right) && (nums[left] == nums[left + 1])) {
left++;
}
/* 更新right与left */
left++, right--;
}
}
}
}
/* 返回值处理 */
*returnSize = index;
int *column = (int *)malloc(sizeof(int) * index);
for (int i = 0; i < index; i++) {
column[i] = 4;
}
*returnColumnSizes = column;
return res;
}
```
### Java
```Java